Wastewater treatment plants occasionally are installed or settle to an out of level state. This can cause improper performance of existing weir systems if they are not properly calibrated or adjusted. Typical systems use weir plates installed in such a manner that they can be adjusted up or down to restore them to the proper level when a tank settles out of line.
U.S. Pat. No. 5,104,528 to Christie discloses a floating decanter apparatus for decanting supernatant from a vessel or basin without drawing floating solids or scum (See moving tube 68, FIG. 2). The apparatus includes a weir with a float for buoyantly supporting the weir in the basin. However, the float is not utilized for self-leveling purposes, but rather to move the weir in a vertical direction.
U.S. Pat. No. 3,849,308 to Westerman provides a container floatably supported on a liquid surface between exterior floats (col. 2, third paragraph). While floats are utilized in this apparatus, they are not utilized in the same manner as the present invention.
U.S. Pat. No. 1,107,391 to Welch shows floats 18 and screens 19. The floats are utilized on the device to automatically maintain itself at a predetermined height relative to the heavier liquid so that the lighter liquid will be collected by the device and carried away for future use. This apparatus is mainly utilized for separating oil from the surface of water.
U.S. Pat. No. 4,010,103 to Morgan, et al. shows a skimmer which automatically pivots in response to different oil levels. This apparatus utilizes floats in an automatic oil/water separating device.
U.S. Pat. No. 5,378,376 to Zenner ( see particularly FIG. 4) shows a floating weir which "automatically and continually senses"(col. 6, last paragraph). This system is directed to vertical movement of the weir rather than the leveling adjustment.
U.S. Pat. No. 4,802,592 to Wessels shows a floating weir in a floating box in a liquid skimmer apparatus. This system is also directed to fluid level control rather than a self-leveling weir.
French Patent No. 2,560,903 to Vidon shows a floating collector that prevents floating objects from entering the discharge tube. This configuration is also directed to the vertical movement of the apparatus.
U.S. Pat. No. 3,970,556 to Gore shows a floating skimmer (claim 1) for cleaning the surface of the liquid around the skimmer. Floatation and ballast chambers in the outer body are utilized to regulate the level of floatation of the weir. Again, the floatation mechanism is utilized in relation to vertical movement with the level of fluids in the apparatus.
U.S. Pat. No. 4,094,338 to Bauer shows a constant discharge rate device of general interest. The apparatus utilizes floatation means around the weir.
None of these references disclose the use of floats in a self-leveling weir that is a part of the apparatus for sludge separation. Unlike the prior art, the present invention is not drawn to the utilization of the floats to control the vertical movement of the weir. Instead, the floats of the invention are utilized in a self-leveling rotational movement of the weir about a fixed outlet pipe in order to adjust the horizontal leveling of the weir.